Accompanied by accelerated development of computer and integrated circuit technologies, information security and privacy are attracting increasing attentions. Physical Unclonable Function (PUF) circuit provides an approach for enhancement of information security by extracting texture features of hardware. Such technology serves as “DNA Feature Identification Technology” in the field of integrated circuit. Silicon based PUF circuit is one of major research focuses of PUF circuit, which makes use of slight process deviation (represented by varied time delay, current and voltage) to unit circuits with the same structural and designing parameters to produce a large number of identifications (IDs) based on corresponding contrast mechanism. Those IDs have features of unclonability, randomness and uniqueness. The deviations can fall into two categories: The first one is deviation to process parameters as incurred by deposition and uneven diffusion of doping agent, including doping concentration, oxidation thickness, diffusion depth and so on; the second one is deviation to geometrical scale as determined by photolithography precision, including deviation to width and length of transistor. PUF circuit has extensive application in such information security fields as device authentication, secure key generation and IP protection.
As PUF circuit is designed based on minor deviation to process parameters during manufacturing of IC, circuit function is vulnerable to impact from such factors as supply voltage, temperature and ageing. Reliability refers to a property that ensures normal operation of PUF circuit under the impact from various factors, which serves as one of important performance indicators for PUF circuit. Reliability of PUF circuit has tremendous impact on safety of the system which embedded PUF circuit; therefore, highly reliable PUF circuit has become a focus of current studies and designs.
Thus, it is of vital importance to design a high-reliability multi-port PUF circuit based on NMOS zero temperature coefficient point, featuring in high uniqueness and randomness.